I am glad to see i am not alone with this very annoying issue. I have an '09 XL1200C Sportster. It only has 4500 miles on it. It has never been in the rain or has never set outside overnight. I run Shell 93 Octane or BP 93 in it. My 'low-fuel' light comes on after about 8-10 miles no matter how much is in my tank. If i baby it around under 55 MPH it might stay off a little longer. As soon as it gets up to highway speed, it comes on. I was thinking that the dealership might have accidentally messed it up while I had it in there getting a Screamin' Eagle Programmer installed and a Stage 1 Air kit. I don't want to think that. But...
Anyway, is there a fix that I can do myself before I have to cough up a bunch for them to look at it?

 

Mine 2007 1200 Custom fuel light just keep on turning on there...I bought this bike 2nd hand and doesn't know what happen. I bring to harley agent and they say is the fuel sensor problem. Any advice here?